|Year|Driver|Constructor|Location|Report|
|---|---|---|---|---|
|1992|Nigel Mansell|Williams-Renault|Hermanos Rodriguez|Report|
|1991|Riccardo Patrese|Williams-Renault|Hermanos Rodriguez|Report|
|1990|Alain Prost|Ferrari|Hermanos Rodriguez|Report|
|1989|Ayrton Senna|McLaren-Honda|Hermanos Rodriguez|Report|
|1988|Alain Prost|McLaren-Honda|Hermanos Rodriguez|Report|
|1987|Nigel Mansell|Williams-Honda|Hermanos Rodriguez|Report|
|1986|Gerhard Berger|Benetton-BMW|Hermanos Rodriguez|Report|
|1985 - 1971|Not held|Not held|Not held|Not held|
|1970|Jacky Ickx|Ferrari|Magdalena Mixhuca|Report|
|1969|Denny Hulme|McLaren-Ford|Magdalena Mixhuca|Report|
|1968|Graham Hill|Lotus-Ford|Magdalena Mixhuca|Report|
|1967|Jim Clark|Lotus-Ford|Magdalena Mixhuca|Report|
|1966|John Surtees|Cooper-Maserati|Magdalena Mixhuca|Report|
|1965|Richie Ginther|Honda|Magdalena Mixhuca|Report|
|1964|Dan Gurney|Brabham-Climax|Magdalena Mixhuca|Report|
|1963|Jim Clark|Lotus-Climax|Magdalena Mixhuca|Report|
|1962|Trevor Taylor  Jim Clark|Lotus-Climax|Magdalena Mixhuca|Report|

Question: what is the total number of years the event was not held?
Answer: 14